A metal sphere of radius R is charged to a pontital V . (a ) Find the electrostatic energy stored in the electric field within a concentric sphere of radius 2 R . (b )Show that the electrostatic field energy stored outside the sphere of radius 2R equals that stored within it .

Explanation

To solve the problem step by step, we will break it down into parts (a) and (b) as given in the question.

### Part (a): Find the electrostatic energy stored in the electric field within a concentric sphere of radius 2R.

1. **Understanding the Setup**:
We have a metal sphere of radius \( R \) charged to a potential \( V \). There is an outer concentric sphere with radius \( 2R \).

2. **Charge on the Inner Sphere**:
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